Notched-bar-testing machine



J. C. W. HUMFREY.

NOTCHED BAR TESTING MACHINE.

APPLICATION FILED NOV.25, I9I9.

1356,82 1 Patented 0m. 26, 1920.

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UNITED STATES PATENT OFFICE.

JOHN CHARLES wILLIs H IVIFR IY, OF LONDON, ENGLAND.

NO'ICI-IED-BAR-TESTIN G MACHINE.

TO aZZ whom it'may concern:

Be it known that 1, JOHN CHARLns WILLIs HUMFREY, a subject ofthe King of Great Britain and Ireland, residing at 40 Grosvenor Gardens, London S. W. 1, England, have invented new and useful Improvements in Notched-Bar-Testing Machines, of which the following is a specification.

This invention relates to testing machines for use in testing notched bars such as are usually broken inmachines of the Izod or Charpy type and my inventionjconsists in an improved construction of machine which is capable of producing upon a chart during a test a continuous auto-graphlc curve expressing the relation at any moment hetween'the bending moment applled to the test piece or specimen, andthe angular distortion which the bending moment produces in it; and further my improvedmachine is provided with apparatus for directly and visually indicating 'on'a graduated d al, the energy expended in bending or break ng the test piece. 7

My invention will be better understood on reference to the accompanying sheet of drawings in which:-

Figure 1' is a front elevation of my 1mproved testing machine, and Fig. 2 is a plan view of same. p The same letters refer to similar parts in both views.

According to my invention I construct my improved machine with two principal parts, the first being a vise a of any suitable form for holding the test piece I) the said vise a being mounted upon a table or bed plate 0 and the second being a special form of lever by which a bending moment can be applied to the test piece. The test "piece b is placedin the vise a so that it is gripped up to the center line of the notch, the 1on-. gitudinal axis of the test piece being horl.

zontal and the notched face being vertical.

The special form of lever above mentioned consists of three principal parts, viz,

an Lshaped socket cl recessed or slotted to receive the projecting end of the test piece b; a rigid (preferably tubular) bar d secured to the upper end of the 'L shaped socket Z and a flexible spring steelbar d attached to the lower portion of the socket d.

Specification of Letters Patent.

Patented Oct. 26, 19,20. Application filed Nov-ember 25, 1919.- Serial NO. 340,560;

The flexible 53.1 02 is of Such dimensions that if a force'is applied-at its free'end at right angles to its lengthsuflicient to break the test piece 6 through thenotch, a definite measurable deflection is produced along'it,

but it: is nowhere stressed above its elastic 7 limit. r r

The rigid tubular bar al has mounted upon it a pen carriage capable of sliding smoothly along it. To one end of the pen carriage e is attached a flexible wire f which passes at right anglesaround a horizontally placed pulley g mounted on a bracket 9' near the socket end of the rigid bar al and is secured to a fixed point hon the bed plate 0. To the other end of the-pen carriage e is attached another flexible wire 2' which passes around a vertically placedpulley On the end of the rigid'bar d and then underneath it and secured to an elastic cord or spring is anchored to the socket (Z. By this arrangement any angular displacement of the test piece Z9 causes thepen carriage e to move a] proportional distance along the bar d Y i The fiexiblesp-ring' steel bar 61 has secured to it a table Z upon which are placed the sheets or cards to receive the autographic records. pen carriage e:has its pointresting upon this last named table Z. supported at its free end upon small wheels m or by a distance piece or pieces sliding over the base plate 0.

On the rigid bar (Z I secure a bearing n the lower end of this vertical shaft 0 is mounted a. horizontal disk wheel g which in turn rests upon the edge of an upright wheel 1" supported on a shaft 1 placed at any convenient angle to the flexible bar d and carried in brackets 83 from the table Z attached to said bar 0Z 011 they last mentioned horizontal shaft r is alsozinounted a 'A pen e carried in the The flexible bar 03 is {in which is .free to move, a vertical shaft 0 graduated dial t which rotates with the shaft, and the extent of which rotation is,

.approximately in the direction of the radius .by meansof-a suitable'gage. Force is thenindicated by means of a stationary pointer u placed on any convenient ad acent fixture.

Alternatively the pointer may revolve with the shaft and the dial be stationary.

The procedure in carrying out a test with my improved machine is as follows The test piece Z) is firmly fastened in the vise a so that the bottom of the notch is in line with the exterior face of the jaws as shown in Fig. 2. The socket end 03 of the lever 03 is fitted over the protruding end of the test piece 6 to a distance from the vise a which can be kept constant for all tests applied to the end of the flexible, bar 42 and forthispurpose a chain and winch are shown in the accompanying drawings. The flexible bar (Z is bent by this force, and thus causes the table Z to move relatively to the pen 6 through an arc whose length is proportional to-the force applied. At the same timeany angular distortion of the test piece Z) produced by'the force causes the pen carriage e to movejalong the rigid'bar (Z and thus tend to draw a straight line on the card to the arc; A curve is thus described from which a; full history of the test can be observed and the details of the various factors determined; the'area inclosed by the curve being proportional to the work done. The

preliminary standardization of the flexible bar d isaeasily' obtained byfhanging on the. movement of the cord 7 over the pulley 7) tends to revolve the horizontal shafts r bythe friction between the wheels 7 and 1 on the respective shafts 0 and T The extent of the rotation of the horizontal shaft r during a test is governed at each instant I test piece) partly by the rotation of the vertical shaft 0 e. due to the bending of the testpiece b), and partly by the deflection of the flexible bar 0% carrying the horizontal shaft 9" (i. e. by the bending moment applied to the stant of the test is proportional to the integral of these two factors, 6. e. to the work expended. The before mentioned rotating graduated .dial 6 with'its complementary fixed. pointer 10 shows the extent of the ro 'tati'on which by meansof thegraduations on the dial t is also expressed in terms of work done.- l V to be movable laterally against the pressure The total rotation at any in- W' hile primarily intended for slow testing,

it having-been demonstrated by several investigators that such slow tests on notched bars give results of equal value with impact tests, my improved machine with a few modifications can also be used for very rapid tests. i. r

I am aware that it has hitherto been proposed in metal bend testing machines to hold 7 one endof the test piece in a fixed, clamp or vise, and the other end in a socket on a movable but rigid member to which ispivoted. a rigid operating handle with opposed lateral springson either side, bearing against abutments on the rigid member or alternatively the handle itself is'a spring and likewise the said rigid. arm carries a chart table and the fiexiblehandle carries a pencil to mark thereon. Also. it has been proposed'in a metal *bend testing machine forthe vise of coiled springs and for the movement of the vise due to the stressing of the testpiece,.to be recorded-on a chart by means of a spring actuated or weightcontrolled pencil carriage connected to the said vise. The

above described arrangements however appertain to the breaking of test pieces, which are not notched, by means of a series of deflections to either side of the original axis, and-no provision is madeas in my invention for breaking a notched test piece by means of a single deflection in one direction only, and at the same time recording aut'ographig cally in a single continuous curve the exact relation between the bending moment applied to the test piece and the angular distortion which this bending moment produces at each stage of the test, starting from the original application of the load up to the i bending moment required, and from thence down to the point at which the test piece completely fractures through the notch.

Having now described myinvention what I claim as new and desire to secure by Let- 120 ters Patent is a V 1. A notched bar testing machine having a vise mounted on'a bed plate, an L shaped socket fittedwith a rigid bar and a flexible bar, a pen carriage and penslidably mo'unted on the rigid bar and controlled in its 'movements by a spring and cords nassing over pulleys, a chart table secured to'the flexiblebar, and means for actuating the.

lever'substantially as herein described.

1,356,821 I V p f8 2'. A notched bar testing machine having a Vise mounted on a bed plate, an L shaped socket fitted with a rigid and flexible bar, a qontrolled sliding pen carriage and pen mounted on the rigid. bar, a chart table secured to the flexible bar, also a bearing on the rigid bar carrying a vertical shaft with upper grooved cord pulley and lower horizontal disk Wheel resting on an upright wheel carried in a horizontal shaft support- 10 ed in bearings from the chart table, said v shaft also carrying a graduated dial with co- JOHN CHARLES WILLIS HUMFREY.

whereof I have signed'my 15 

